This was adapted from https://github.com/BerntA/GameServerBrowser/
which was not being hosted. I also implemented the blacklist from https://github.com/Ch0wW/goldsrc-fake-servers-firewall
to prevent some of the fake servers from being shown. This is still not a good browser for popular titles; I made this page to supplement the other tools that are available.
gametracker.com is a better interface for many popular titles but I can add any arbitrary third-party mod here.
cs2browser.com is a good interface for browsing Counter-Strike servers, and includes additional filters for game modes.